Mahakala is worshipped in esoteric Buddhism as a dharmapala or Protector of Buddhist Law'. Generally speaking, Mahakala has never played a significant role in the main stream of Chinese Buddhism, but since the late ninth century the Mahakala cult has flourished in Yunnan province in the southwest corner of China. This paper will focus on the iconography of the Buddhist Mahakala images in Yunnan during the Nanzhao and Dali periods in an attempt to establish, if possible, iconographic sources of Yunnanese Mahakala imagery. The Yunanese Mahakala is commonly depicted as the deity holding the sword, the trident, the skull cup, the drum, the noose and the rosery as his standard attributes of which the skull cup, the sword and the rosery are commonly seen in the hands of Indian Mahakala images. It is quite different from Chinese and Tibetan Mahakala imagery iconographically. This fact indicates that the Mahakala cult and its iconography were brought to Yunnan from India directly, and China and Tibet had little influence on the Yunnanese Mahakala. According to Yunnanese local history, many foreign monks came to Yunnan from India in the Nanzhao period. It is quite possible that the Mahakala cult was introduced to Yunnan by these Indian missionaries. Since then, Mahakala has taken its root in Yunnan. As Mahakala developed in Yunnan, the divinity began to take some new roles, and certain innovative icons were created. In Buddhist traditions Mahakala has various manifestations. Outside of Yunnan, the God of Longevity is never among these. Moreover, the images of the Daan Yaocha and the Jinbojialuo are not encountered in any other Buddhist tradition. They may well be Yunnanese innovations. Another distinctive feature of the Yunnan Mahakala worthy of note is that the deity is often paired with Vaisravana This pair are completely unknown in India, Tibet, or China.